In purlin supported sheet metal roof systems, such as typical standing seam roof constructions, the all metal construction combined with the relatively thin sheet metal roof panels require the inclusion in such roofs of a substantial thickness of heat insulating material. It is known in constructions of this type to install blankets of heat insulating material as the roof is being constructed, normally by laying the blanket of insulating material over the purlins and securing the blanket in place by installing the roof panel mounting clips on top of the blanket, the self tapping screws securing the mounting clips to the purlins passing through the insulating blanket. (See, for example, copending application U.S. Ser. No. 206,822, filed Nov. 14, 1980 and assigned to the assignee of the present application which I incorporate herein by reference).
As pointed out in the aforementioned application, U.S. Ser. No. 206,822, the clamping of the insulating blanket in place by the mounting of the roof panel mounting clips necessarily compresses the blanket along the top of the purlin. Because the blanket must be compressed in this particular type of installation, the thicker the blanket of insulating material employed, the more difficult it becomes to install by this method. As a practical matter, blankets of thickness over six inches pose substantial installation problems where the blanket is to be clamped between the purlin and the roof panel mounting clips. As is recognized in U.S. Pat. No. 4,058,949, "practical considerations limit roof insulation configurations to panels of three to four inches in thickness" for an installation of this type. In U.S. Pat. No. 4,058,949, this problem is solved by employing two layers of relatively thin blankets instead of a single layer thick blanket, however, the double layer blanket installation of U.S. Pat. No. 4,058,949 requires the mounting of a spacer upon the purlins between the two layers to clamp the lower layer to the purlin and to provide a support surface for the upper layer which is held in position by the mounting clip. Other approaches are disclosed in U.S. Pat. Nos. 3,513,614; 4,117,641; 3,511,011; and 4,075,806.
The present invention is especially directed to a resilient clip system which resiliently clamps a relatively thin blanket of insulating material to the purlins in a manner such that the blanket is formed with a depressed pocket between adjacent purlins which is suitable for receiving unfaced batts of insulation material which may be simply placed in position as the roof panels are being installed.